Drum Washing Machine

ABSTRACT

A drum for a laundry washing machine (W) has side walls ( 50, 51, 52, 53; 110, 111, 112, 113 ) defining a laundry receiving space ( 53, 113 ). At least one of the side walls is circular and comprises a plurality of openings ( 41, 61 ) for the passage of a liquid therethrough. The drum comprises at least a circular member ( 55, 65, 115 ) circumferentially associated to an inner portion ( 50   a,    110   a ) of the circular side wall. The circular member defines a chamber ( 59, 119 ) for receiving the liquid from at least one receiving opening ( 43, 163 ) of the openings and comprises at least one aperture ( 66, 126, 266 ) facing the laundry receiving space suitable to modify the flow of the liquid from the at least one receiving opening to the laundry receiving space.

The present invention concerns the field of laundry washing techniques. In particular, the present invention refers to a drum for a laundry washing machine.

BACKGROUND ART

Nowadays the use of laundry washing machines, both “simple” laundry washing machines (i.e. laundry washing machines which can only wash and rinse laundry) and washing-drying machines (i.e. laundry washing machines which can also dry laundry), is widespread.

In the present description the term “laundry washing machine” will refer to both simple laundry washing machines and laundry washing-drying machines.

Laundry washing machines generally comprise an external casing provided with a washing tub inside which there is a rotatable perforated drum in which the laundry is placed.

A loading/unloading door ensures access to the tub and the drum.

Laundry washing machines typically comprise a detergent supply unit containing washing and/or rinsing products (i.e. detergent, softener, etc.).

Laundry washing machines of known type typically comprise a water inlet circuit for supplying water inside the tub and also a recirculation circuit adapted to drain the liquid from the bottom of the tub and to re-admit such liquid into an another part of the tub. The water inlet circuit and the recirculation circuit preferably comprise ducts terminating with respective injection nozzles from which the water or the liquid is sprayed toward the perforated drum. Usually the ducts of the water inlet circuit and of the recirculation circuit terminate at common spraying nozzles.

The water or the liquid admitted in the tub either through the water inlet circuit or the recirculation circuit reaches the laundry inside the drum by means of the holes present in the peripheral wall of the perforated drum.

A laundry washing machine with a perforated drum belonging to the know technique is disclosed in document U.S. Pat. No. 2,357,909.

In this document a substantially cylindrical tub and a perforated drum arranged therein is described.

The perforated drum comprises a substantially cylindrical side wall. The drum is perforated throughout substantially the extent of the side wall. The side wall comprises a number of first small opening and a series of second larger openings which are circumferentially spaced around the sidewall in groups which are spaced axially of the drum.

The laundry washing machine further comprises a conduit for admitting fresh water into the tub and a plurality of water nozzles which are spaced apart and disposed, respectively, in the planes of the axially-spaced groups of large openings.

The laundry washing machine also comprises a re-circulation circuit wherein the liquid from the bottom of the tub is withdrawn through a conduit and conveyed to the water nozzles.

The water conveyed to the nozzles is discharged by means of the nozzles into the drum through the circumferentially-spaced large openings.

The large openings of the perforated drum enhance the water flow entering into the drum for wetting the laundry.

The water enters radially inside the drum towards the centre of the drum itself.

However, the laundry washing machine with perforated drum above described belonging to the known art poses some drawbacks.

A first drawback posed by this known technique is constituted by the fact that the clothes disposed inside the drum may be damaged during the rotation of the drum due to the large size of the openings, especially when the drum is made rotate at high speed with the clothes subjected to a high centrifugal force.

A further drawback of the known technique is represented by the fact that the water is not uniformly distributed inside the drum but it is concentrated in correspondence of the large openings.

The main object of the present invention is therefore to overcome said drawbacks.

In particular, it is one object of the present invention to provide a drum for laundry washing machine which allows a gently treatment of the clothes during rotations.

Another object of the present invention is to provide a drum for laundry washing machine which allows a more uniform distribution of water/liquid to the clothes than the laundry washing machine of known type.

DISCLOSURE OF INVENTION

The present invention therefore relates, in a first aspect thereof, to a drum for a laundry washing machine comprising side walls defining a laundry receiving space, at least one of said side walls being circular and comprising a plurality of openings for the passage of a liquid therethrough, the drum comprising at least a circular member circumferentially associated to an inner portion of said circular side wall, said circular member defining a chamber for receiving said liquid from at least one receiving opening of said openings and comprising at least one aperture facing said laundry receiving space suitable to modify the flow of said liquid from the at least one receiving opening to said laundry receiving space.

Preferably the circular member is fixed to the inner portion of the circular side wall.

More preferably the circular member is associated to the inner portion of the circular side wall in a removable way.

Advantageously the circular member is a portion of circumference.

In a preferred embodiment the circular member has a substantially U-shaped section.

In a further preferred the circular member has a substantially trapezoidal-shaped section.

Preferably the size of the aperture is less than the size of the receiving opening.

Advantageously the plurality of openings of the circular side wall comprises a first plurality of openings and a second plurality of openings wherein the size of the first plurality of openings is less than the size of the second plurality of openings.

Opportunely the circular member is associated to the inner portion of the circular side wall in correspondence of the second plurality of openings.

In a preferred embodiment at least one of the side walls is a rear side wall and the circular member is associated to the inner portion of the circular side wall in a position close to the rear side wall.

Preferably the drum further comprises at least one lifter associated to the inner portion of the circular side wall.

Advantageously the lifter defines a chamber for receiving the liquid from the at least one receiving opening and comprises at least one aperture facing the laundry receiving space suitable to modify the flow of the liquid from the at least one receiving opening to the laundry receiving space.

Preferably the chamber of the at least one lifter communicates with the chamber of the circular member.

In a preferred embodiment the at least one lifter is fixed to the inner portion of the circular side wall.

Advantageously the at least one lifter is associated to the inner portion of the circular side wall in a removable way.

Preferably the at least one lifter is fixed to the circular member.

In a preferred embodiment the at least one lifter and the circular member are formed as a single piece construction.

In a second aspect thereof, the present invention concerns a laundry washing machine comprising a casing supporting a washing tub external to a washing drum suitable to receive the laundry to be washed, said washing drum being a drum as described above.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the present invention will be highlighted in greater detail in the following detailed description of some of its preferred embodiments, provided with reference to the enclosed drawings. In the drawings, corresponding characteristics and/or components are identified by the same reference numbers. In particular:

FIG. 1 shows a isometric view of a laundry washing machine according to a first embodiment of the invention;

FIG. 2 shows a isometric view of a drum for the laundry washing machine of FIG. 1 according to a first embodiment of the invention;

FIG. 3 shows a isometric view of some particulars of the drum shown in FIG. 2;

FIG. 3A shows a section view along line III°-III° of FIG. 3;

FIG. 3B shows a construction variant of FIG. 3A;

FIG. 4 shows a longitudinal section view of the drum of FIG. 2;

FIG. 4A shows an enlarged detail of FIG. 4;

FIG. 5 shows a construction variant of the drum of FIG. 2

FIG. 6 shows a isometric view of some particulars of the drum shown in FIG. 5;

FIG. 7 shows a longitudinal section view of the drum of FIG. 5;

FIG. 8 shows a further construction variant of the washing machine of FIG. 1;

FIG. 9 shows a isometric view of a drum for the laundry washing machine of FIG. 8;

FIG. 10 shows a isometric view of some particulars of the drum shown in FIG. 9;

FIG. 10A shows a section view along line X°-X° of FIG. 10;

FIG. 11 shows a longitudinal section view of the drum of FIG. 9.

DETAILED DESCRIPTION OF THE INVENTION

A laundry washing machine W with a drum 1 according to a first embodiment of the invention is described here below with reference to Figures from 1 to 4.

The laundry washing machine W shown in FIG. 1 is a front loading washing machine. The present invention has proved to be particularly successful when applied to front loading laundry washing machines. It should in any case be underlined that the present invention is not limited to this type of application. On the contrary, the present invention can be usefully applied to different types of loading washing devices, as for example top loading laundry washing machines or laundry washing-drying machines.

The laundry washing machine W comprises an external casing or casing 2, in which a washing tub 3 is provided that contains a rotatable perforated drum 1, where the laundry to be washed can be loaded.

The tub 3 and the drum 1 both have preferably a substantially cylindrical shape.

A hollow space is defined between the tub 3 and the drum 1.

The casing 2 is provided with a loading/unloading door, not illustrated, which allows access to the washing tub 3 and the drum 1.

The tub 3 is preferably suspended in a floating manner inside the casing 2, advantageously by means of a number of coil springs and shock-absorbers, that are not illustrated herein.

The tub 3 is preferably connected to the casing 2 and/or the door by means of an elastic bellows 7, or gasket.

The drum 1 is advantageously rotated by an electric motor which preferably transmits the rotating motion to the shaft 14 of the drum 1, advantageously by means of a belt/pulley system. In a different embodiment of the invention, the motor can be directly associated with the shaft 14 of the drum 1.

A water inlet circuit 5 is arranged in the upper part of the laundry washing machine W and is suited to supply water and washing/rinsing products (i.e. detergent, softener, etc.) into the tub 3.

The water inlet circuit 5 advantageously comprises a removable drawer 6 provided with various compartments suited to be filled with washing and/or rinsing products.

In the embodiment herein described, the water is advantageously supplied into the tub 3 by making it flow through the drawer 6 and through a supply pipe 9 which extends toward the front side of the washing machine 1. The supply pipe 9 is provided with an output 9 a placed partially inside the bellows 7 in the proximity of the front door.

In a preferred embodiment, the water which reaches the tub 3 can selectively contain one of the products contained in the compartments of the drawer 6, or such water can be clean and in this case it may reach the tub 3 directly, bypassing the compartments of the drawer 6.

This may depend on the phase of the washing cycle selected. In the initial phases of the washing cycle, for example, the products are conveyed into the tub 3 over the laundry. In other phases, as for example during the rinsing phase, only water in conveyed into the tub 3.

In an alternative embodiment of the invention, a further separate water supply pipe can be provided, which supplies exclusively clean water into the tub 3.

The water inlet circuit 5 also preferably comprises a water flow sensor, for example a flow meter, which makes it possible to calculate the quantity of water supplied into the tub 3.

The laundry washing machine W advantageously comprises a water outlet circuit 25.

The water outlet circuit 25 advantageously comprises a drain pump 26, a first pipe 27 connecting the tub 3 to the drain pump 26 and an outlet pipe 28 ending outside the casing 2. The water outlet circuit 25 is suited to drain the liquid, i.e. dirty water or water mixed with washing and/or rinsing products, from the tub 3 to the outside.

The water outlet circuit 25 is advantageously provided with a recirculation circuit 30 adapted to drain liquid from a bottom region of the tub 3 and to re-admit such a liquid into a higher region of the tub 3.

The recirculation circuit 30 comprises a recirculation pump 29 and a recirculation pipe 31. The recirculation pipe 31 advantageously ends with two injection nozzles 32, 33 in an upper region of the tub 3 and with a third injection nozzle 34 in the proximity of the front door.

The drain pump 26 and the recirculation pump 29 are properly controlled in order to allow selective drainage of the liquid from the tub 3 towards the outside through the outlet pipe 28 or towards the upper region of the tub 3 through the recirculation pipe 31.

In case of drainage of the liquid from the tub 3 towards the outside only the drain pump 26 is activated. In case of drainage of the liquid from the tub 3 towards the towards the upper region of the tub 3 only the recirculation pump 29 is activated.

In a further embodiment, not illustrated, the recirculation circuit may comprise a dedicated recirculation pipe connecting a bottom region of the tub with an higher region of the latter, and provided with a dedicated recirculation pump; in this case the recirculation circuit is advantageously completely separated from the water outlet circuit.

The drum 1 comprises a cylindrical side wall 50, a rear side wall 51 and a front side wall 52. The side walls 50, 51 and 52 define a laundry receiving space 53 where the laundry to be washed is loaded.

The front side wall 52 comprises an aperture 54, substantially aligned with the loading/unloading door of the laundry washing machine W, from which the laundry is loaded/unloaded.

The drum 1 is also advantageously provided with three inwardly extending lifters 61, 62 and 63, as better visible in FIG. 3. The lifters 61, 62 and 63 extend over the inner surface 50 a of the cylindrical side wall 50 substantially from the rear side wall 51 to the front side wall 52.

The lifters 61, 62 and 63 are circumferentially spaced and engage the laundry as the drum 1 is rotated.

The lifters 61, 62 and 63 raise the laundry contained in the laundry receiving space 53 toward the top of the drum 1 and then release the laundry to cause the laundry to be dropped to the bottom of the drum 1, in accordance with the rotation of the drum 1.

The cylindrical side wall 50 of the drum 1 is provided with openings 41, as better visible in FIG. 2.

The openings 41 comprises a plurality of first openings 42 preferably uniformly distributed over the cylindrical side wall 50. The first openings 42 preferably have a circular shape with a diameter preferably comprised between 2 mm and 4 mm.

More generally, the first openings may have different shape than the circular one shown in the figures, as for example an oval shape. The maximum size of each of the first openings is preferably less than 4 mm.

The openings 41 further comprises a plurality of second openings 43 preferably distributed circumferentially over the cylindrical side wall 50 in two parallel rows 43 a and 43 b. Each of the two parallel rows 43 a and 43 b of the second openings 43 advantageously faces a respective injection nozzle 32, 33 of the recirculation pipe 31.

Second openings 43 advantageously have a larger size than the first openings 42.

The second openings 43 preferably have a circular shape with a diameter comprised between 8 mm and 20 mm.

Second openings may have different shape than the circular one shown in the figures, as for example an oval shape. The maximum size of each of the second openings is preferably less than 20 mm.

Both the first and the second openings 42 and 43 allow the passage of a liquid therethrough, in particular the passage of a liquid from outside of the drum 1 to the laundry receiving space 53.

The larger size of the second openings 43 with respect to the size of the first openings 42 advantageously enhances the passage of the liquid from the injection nozzles 32, 33 to the laundry receiving space 53 inside the drum 1.

The drum 1 advantageously comprises two cover rings 55, 65 which extend circumferentially over the inner surface 50 a of the cylindrical side wall 50. The cover rings 55, 65 face the second openings rows 43 a and 43 b.

Cover rings 55, 65 are substantially equal to each other and therefore only one is described in detail hereinafter.

The cover ring 55 is substantially circular so as to fit the inner surface 50 a of the cylindrical side wall 50. The cover ring 55 comprises three adjacent circular portions 55 a, 55 b and 55 c which are disposed between the lifters 61, 62 and 63, as shown in FIG. 3 where the cover rings 55, 65 and the lifters 61, 62, 63 are illustrated separated from the rest.

Each of the circular portions 55 a, 55 b and 55 c is preferably a portion of circumference.

The cover ring 55 preferably has a substantially U-shaped section, as better shown in FIG. 3A. The cover ring 55 comprises two lateral sides 56, 57 and a link side 58 between the two lateral sides 56, 57. The cover ring 55 in combination with the inner surface 50 a of the cylindrical side wall 50 defines a liquid receiving chamber 59, as shown in FIG. 4A.

The link side 58 of the cover ring 55 advantageously comprises apertures 66 for the communication of the liquid receiving chamber 59 with the laundry receiving space 53 inside the drum 1.

The apertures 66 preferably have a circular shape with a diameter comprised between 2 mm and 8 mm.

The apertures may have different shape than the circular one shown in the figures, as for example an oval shape. The maximum size of each of the second openings is preferably less than 8 mm.

The apertures 66 may have preferably the same shape and size of the first openings 42 of the cylindrical side wall 50.

According to the preferred embodiment of the laundry washing machine W above described, the liquid at the bottom of the tub 3, usually comprising water and/or detergent, may be re-circulated and re-introduced inside the drum 1 by means of the activation of the recirculation circuit 30.

The recirculation pump 29 is activated and the drained liquid may flow from the bottom of the tub 3 along the recirculation pipe 31 up to injection nozzles 32, 33 and 34. In particular, the liquid is sprayed with a proper pressure from the injection nozzles 32, 33 in the upper region of the tub 3 towards the second openings 43 of the cylindrical side wall 50 of the drum 1. The drum 1 advantageously rotates during this recirculation phase. The larger size of the second openings 43 with respect to the size of the first openings 42, as said before, enhances the passage of the liquid inside the drum 1. Part of the liquid may reach the first openings 42 of the cylindrical side wall 50 of the drum 1 and gets in through the first openings 42 inside the drum 1.

The liquid coming from the injection nozzles 32, 33 which gets in through the second openings 43 is received in the liquid receiving chamber 59 formed by the cover ring 55. From the liquid receiving chamber 59 the liquid under pressure is then conveyed through the apertures 66 inside the laundry receiving space 53 along a preferred radial direction R1.

The liquid direction R1 inside the laundry receiving space 53 depends substantially on the orientation of the link side 58 of the cover ring 55 and on the number and size of the apertures 66.

It is clear that in different embodiments such direction may be different and opportunely set according to a different shape of the link side and of the apertures.

Advantageously, the provision of the cover rings 55, 65 with apertures 66 having reduced size with respect to the second opening 43 of the cylindrical side wall 50 avoid damaging of the laundry during the rotation of the drum 1, especially when the drum 1 is made rotate at high speed with the laundry subjected to a high centrifugal force.

In the preferred embodiment herewith described, the cover rings and the lifters are advantageously fixedly connected to each other.

In different embodiments, the cover rings and the lifters may be separated parts.

In a preferred embodiment of the drum of the invention, the cover rings are fixedly connected to the inner surface of the cylindrical side wall, for example by means of snap-fit, screws, welding, gluing or other suited fastening means.

Preferably the cover rings are made of the same material of the cylindrical side wall. In further embodiments the cover rings may be of a different material, as for example plastic.

In another preferred embodiment, the cover rings may be associated to the inner surface of the cylindrical side wall in a removable way. In this case the cover rings may be advantageously replaced. This is particularly useful when the cover rings are damaged or when the cover rings are being replaced with different cover rings having different disposition and/or shape of the apertures. This may advantageously confer different desiderate directions to the liquid.

With reference to FIG. 3B a construction variant of the cover ring 255 is described.

This cover ring 255 differs from the one described above with reference to FIG. 3A for the fact that the lateral sides 256, 257 comprise further apertures 266 for the communication of the liquid receiving chamber 259 with the laundry receiving space 53 inside the drum 1.

Advantageously in the washing machine provided with this cover ring 255 the liquid coming from the injection nozzles 32, 33 reaches the laundry from different directions R1, R2 and R3. This determines a more uniform distribution of the liquid over the laundry.

The liquid directions R1, R2 and R3 inside the laundry receiving space 53 depend substantially on the orientation of the lateral sides 256, 257 and 258 of the cover ring 255 and on the number and size of the apertures 66, 266 formed therein.

It is clear that in different embodiments such directions may be different and opportunely set according to a different shape of the sides and of the apertures.

With reference to Figures from 5 to 7 a construction variant of the drum 71 is described.

This drum 71 differs from the drum 1 shown in FIG. 2 for the different construction of the lifters 81, 82 and 83.

The lifters 81, 82 and 83 are substantially equal to each other and therefore only one is described in detail hereinafter.

The lifter 81 extends inwardly from the inner surface 50 a of the cylindrical side wall 50 and extend longitudinally between the rear side wall 51 and the front side wall 52 of the drum 1.

The lifter is substantially U-shaped, as better shown in FIG. 6, comprising two lateral sides 85 a, 85 b and a link side 85 c between the two lateral sides 85 a, 85 b. The two lateral sides 85 a, 85 b and the link side 85 c have respective smooth outer surfaces in order to engage gently the laundry and avoid laundry damages.

The lifter 81 in combination with the inner surface 50 a of the cylindrical side wall 50 defines a liquid receiving chamber 87.

The lateral sides 85 a, 85 b and the link side 85 c of the lifter 85 advantageously comprise apertures 90 for the communication of the liquid receiving chamber 87 with the laundry receiving space 53 inside the drum 1.

The apertures 90 preferably have an oval shape with a maximum size comprised between 5 mm and 12 mm.

The apertures may have different shape than the oval one shown in the figures, as for example a circular shape. The maximum size of each of the second openings is preferably less than 12 mm.

At least one of the second openings 43 of the cylindrical side wall 50 communicates with the liquid receiving chamber 87 of the lifter 81. More particularly, one opening 43′a of the first row 43 a of the second openings 43 communicates with the liquid receiving chamber 87.

Preferably also at least one of the first openings 42 of the cylindrical side wall 50 may communicate with the chamber 87.

Preferably the liquid receiving chamber 87 of the lifter 81 may communicate with the liquid receiving chambers 59 of the adjacent cover rings 55, 65.

The lifter 81 is advantageously associated to the inner surface 50 a of the cylindrical side wall 50 in a removable way. Preferably a snap fit connection between the lifter 81 and the cylindrical side wall 50 is provided. The snap fit connection comprises two couples of attaching elastic wings 91-94 which engage respective receiving holes 97-100 in the cylindrical side wall 50.

The lifter 81 further comprises two threaded holes 88 for receiving fixing screws, not illustrated, passing through respective holes 78 of the side wall 50 of the drum 1.

The lifter 81 therefore may be easily detached and, in case, replaced with a new one. The new lifter may have, for example, a new configuration of the apertures.

In a further embodiment, the lifter may be fixedly connected to the inner surface of the cylindrical side wall, for example by means of snap-fit, screws, welding, gluing or other suited fastening means.

According to this embodiment the liquid coming from the injection nozzles 32, 33 is sprayed with a proper pressure from the injection nozzles 32, 33 in the upper region of the tub 3 towards the second openings 43 of the cylindrical side wall 50 of the drum 1.

The liquid coming from the injection nozzles 32, 33 which gets in through the second openings 43 is received in the liquid receiving chamber 87 of the lifter 81. From the liquid receiving chamber 87 the liquid under pressure is then conveyed through the apertures 90 inside the drum 1 along different directions according to the orientations of the apertures 90 along the lifter 81.

Advantageously the liquid coming from the injection nozzles 32, 33 reaches the laundry from different directions. This causes an enhanced and uniform distribution of the liquid over the laundry.

The liquid directions inside the laundry receiving space depend on the orientation of the lateral sides 85 a, 85 b and 85 c of the lifter 81 and on the number and size of the apertures 90 formed therein.

It is clear that in different embodiments such directions may be different and opportunely set according to a different shape of the lifters and of the apertures.

In this embodiment the lifters 81, 82 and 83, therefore, do not have only the function of raising the laundry contained in the laundry receiving space 53.

In a preferred embodiment a lifter and at least one of the adjacent circular portions of the cover rings may be formed as a single piece construction, obtained for example by means of an injection moulding process.

The lifter and the adjacent circular portions of the cover ring are preferably associated to the inner surface of the cylindrical side wall of the drum in a removable way.

This is particularly useful when the cover rings or the lifters are damaged or when the cover rings or the lifters are being replaced with new ones having different disposition and/or shape of the apertures. This may advantageously confer different desiderate directions to the liquid.

Preferably the lifters are made of the same material of the cover rings.

With reference to Figures from 8 to 11 a construction variant of a laundry washing machine W and of the drum 101 is described.

Apart from the drum 101, the laundry washing machine W shows in FIG. 8 differs from the laundry washing machine W described with reference to FIG. 1 only for the fact that the recirculation pipe 31 ends with a rear injection nozzle 35 in a rear upper region of the tub 3 instead of the two injection nozzles 32, 33 in the upper central region of the tub 3.

The drum 101 comprises a cylindrical side wall 110, a rear side wall 111 and a front side wall 112. The side walls 110, 111 and 112 define a laundry receiving space 113 where the laundry to be washed is loaded.

The front side wall 112 comprises an aperture 114, substantially aligned with the loading/unloading door of the laundry washing machine W, from which the laundry is loaded/unloaded.

The drum 101 is also advantageously provided with three inwardly extending lifters 121, 122 and 123, as better visible in FIG. 10. The lifters 121, 122 and 123 extend over the inner surface 110 a of the cylindrical side wall 110 substantially from the rear side wall 111 to the front side wall 112 of the drum 101.

The lifters 121, 122 and 123 are circumferentially spaced and engage the laundry as the drum 101 is rotated.

The cylindrical side wall 110 of the drum 101 is provided with openings 161, as better visible in FIG. 9.

The openings 161 comprises a plurality of first openings 162 preferably uniformly distributed over the cylindrical side wall 110. The first openings 162 preferably have a circular shape with a diameter preferably comprised between 2 mm and 4 mm.

More generally, the first openings may have different shape than the circular one shown in the figures, as for example an oval shape. The maximum size of each of the first openings is preferably less than 4 mm.

The openings 161 further comprises a plurality of second openings 163 preferably distributed circumferentially over the cylindrical side wall 110 in a single row 163 a. The row 163 a of the second openings 163 advantageously face the rear injection nozzle 35 of the recirculation pipe 31, the latter shown in FIG. 8.

Second openings 163 preferably have a larger size than the first openings 162. The second openings 163 preferably have a circular shape with a diameter comprised between 8 mm and 20 mm.

Second openings may have different shape than the circular one shown in the figures, as for example an oval shape. The maximum size of each of the second openings is preferably less than 20 mm.

The larger size of the second openings 163 with respect to the size of the first openings 162 advantageously enhances the passage of the liquid from the rear injection nozzle 35 to the laundry receiving space 113 inside the drum 101.

The drum 101 advantageously comprises a cover ring 115 which extend circumferentially over the inner surface 110 a of the cylindrical side wall 110.

The cover ring 115 face the second openings row 163 a. The cover ring 115 is preferably placed in the proximity of the rear side wall 111 of the drum 101.

The cover ring 115 is substantially circular so as to fit the inner surface 110 a of the cylindrical side wall 110. The cover ring 115 comprises three adjacent circular portions 115 a, 115 b and 115 c which are disposed between the lifters 121, 122 and 123, as shown in FIG. 10 where the cover ring 115 and the lifters 121, 122, 123 are illustrated separated from the rest. Each of the circular portions 115 a, 115 b and 115 c is preferably a portion of circumference.

The cover ring 115 preferably has a substantially trapezoidal-shaped section, as better shown in FIG. 10A. The cover ring 115 comprises two lateral sides 116, 117 and a front side 118 between the two lateral sides 116, 117. The lateral sides 116, 117 and the front side 118 define a liquid receiving chamber 119.

The front side 118 of the cover ring 115 advantageously comprises apertures 126 for the communication of the liquid receiving chamber 119 with the laundry receiving space 113 inside the drum 101.

The apertures 126 preferably have a circular shape with a diameter comprised between 2 mm and 8 mm.

The apertures may have different shape than the circular one shown in the figures, as for example an oval shape. The maximum size of each of the second openings is preferably less than 8 mm.

The apertures 126 may have preferably the same shape and size of the first openings 162 of the cylindrical side wall 110.

The lifters 121, 122 and 123 are substantially equal to each other and therefore only one is described in detail hereinafter.

The lifter 121 is substantially U-shaped, as better shown in FIG. 10, comprising two lateral sides 185 a, 185 b and a link side 185 c between the two lateral sides 185 a, 185 b. The two lateral sides 185 a, 185 b and the link side 185 c have respective smooth outer surfaces in order to engage gently the laundry and avoid laundry damages.

The lifter 121 in combination with the inner surface 110 a of the cylindrical side wall 110 defines a liquid receiving chamber 187.

The lateral sides 185 a, 185 b and the link side 185 c of the lifter 121 advantageously comprise apertures 190 for the communication of the liquid receiving chamber 187 with the laundry receiving space 113 inside the drum 101.

The apertures 190 preferably have an oval shape with a maximum size comprised between 5 mm and 12 mm.

The apertures may have different shape than the oval one shown in the figures, as for example a circular shape. The maximum size of each of the second openings is preferably less than 12 mm.

At least one of the second openings 163 of the cylindrical side wall 110 communicates with the liquid receiving chamber 187 of the lifter 121. More particularly, one opening 163′a of the first row 163 a of the second openings 163 communicates with the liquid receiving chamber 187.

Preferably also at least one of the first openings 162 of the cylindrical side wall 110 may communicate with the liquid receiving chamber 187.

Preferably the liquid receiving chamber 187 of the lifter 121 communicates with the liquid receiving chambers 159 of the adjacent cover ring 155 through a communicating channel 191.

The lifter 121 is advantageously associated to the inner surface 110 a of the cylindrical side wall 110 in a removable way. Preferably a snap fit connection between the lifter 121 and the cylindrical side wall 110 is provided. The snap fit connection comprises two couples of attaching elastic wings 291-294 which engage respective receiving holes 297-300 in the cylindrical side wall 110.

The lifter 121 further comprises two threaded holes 288 for receiving fixing screws, not illustrated, passing through respective holes 278 of the side wall 110 of the drum 101.

The lifter 121 therefore may be easily detached and, in case, replaced with a new one. The new lifter may have, for example, a new configuration of the apertures.

In a further embodiment, the lifter may be fixedly connected to the inner surface of the cylindrical side wall, for example by means of snap-fit, screws, welding, gluing or other suited fastening means.

According to the preferred embodiment of the laundry washing machine W above described, the liquid at the bottom of the tub 3, usually comprising water and/or detergent, may be re-circulated and re-introduced inside the drum 101 by means of the activation of the recirculation circuit 30.

The recirculation pump 29 is activated and the drained liquid may flow from the bottom of the tub 3 along the recirculation pipe 31 up to injection nozzles 34, 35.

In particular, the liquid is sprayed with a proper pressure from the rear injection nozzle 35 in the upper and rear region of the tub 3 towards the second openings 163 of the cylindrical side wall 110 of the drum 101. The drum 101 advantageously rotates during this recirculation phase. The larger size of the second openings 163 with respect to the size of the first openings 162, as said before, enhances the passage of the liquid inside the drum 101. Part of the liquid may reach the first openings 162 of the cylindrical side wall 110 of the drum 101 and gets in through the first openings 162 inside the drum 101.

The liquid coming from the rear injection nozzle 35 which gets in through the second openings 163 is received in the liquid receiving chamber 119 formed by the cover ring 115. From the liquid receiving chamber 119 the liquid under pressure is then conveyed through the apertures 126 inside the laundry receiving space 113 along a direction R4, which is preferably directed towards the centre of the drum 101.

Advantageously the liquid coming from the rear injection nozzle 35 reaches the laundry from the rear. This determines a more uniform distribution of the liquid over the laundry.

The liquid direction R4 inside the laundry receiving space 113 depends on the orientation of the front side 118 of the cover ring 115 and on the number and size of the apertures 126 formed therein.

It is clear that in different embodiments such directions may be different and opportunely set according to a different shape of the side and of the apertures.

The provision of the cover ring 115 with apertures 126 having reduced size with respect to the second opening 163 of the cylindrical side wall 110 avoid damaging of the laundry during the rotation of the drum 101, especially when the drum 101 is made rotate at high speed with the laundry subjected to a high centrifugal force.

During the recirculation, as said before, the liquid is sprayed with a proper pressure from the rear injection nozzle 35 in the upper and rear region of the tub 3 towards the second openings 163 of the cylindrical side wall 110 of the drum 101.

The liquid which gets in through the second openings 163 is also received in the liquid receiving chamber 187 of the lifter 121. The liquid also reaches the liquid receiving chamber 187 from the liquid receiving chambers 119 of the cover ring 115 through the communicating channel 191.

From the liquid receiving chamber 119 the liquid under pressure is then conveyed inside the drum 101 through the apertures 190. The liquid enters the laundry receiving space 113 along different directions.

This causes an enhanced and uniform distribution of the liquid over the laundry.

As said for the previous embodiment, such directions may be different and opportunely set according to the orientations of the sides of the lifters and according to the number and size of the apertures.

In a preferred embodiment a lifter and at least one of the adjacent circular portions of the cover rings may be formed as a single piece construction, obtained for example by means of an injection moulding process.

The lifter and the adjacent circular portions of the cover ring are preferably associated to the inner surface of the cylindrical side wall of the drum in a removable way.

This is particularly useful when the cover ring or the lifters are damaged or when the cover ring or the lifters are being replaced with new ones having different disposition and/or shape of the apertures. This may advantageously confer different desiderate directions to the liquid.

Preferably the lifters are made of the same material of the cover ring.

In a preferred embodiment of the drum of the invention, the cover ring is fixedly connected to the inner surface of the cylindrical side wall, for example by means of snap-fit, screws, welding, gluing or other suited fastening means.

Preferably the cover ring is made of the same material of the cylindrical side wall. In further embodiments the cover ring may be of a different material, as for example plastic.

It has thus been shown that the present invention allows all the set objects to be achieved. In particular, it makes it possible to obtain a gently treatment of the clothes during rotations.

It is underlined that the laundry washing machines illustrated in the enclosed figures, and with reference to which some embodiments of the drum according to the invention have been described, are of the front-loading type; however it is clear that the drum according to the invention can be applied as well to a top-loading washing machine, substantially without any modification.

While the present invention has been described with reference to the particular embodiments shown in the figures, it should be noted that the present invention is not limited to the specific embodiments illustrated and described herein; on the contrary, further variants of the embodiments described herein fall within the scope of the present invention, which is defined in the claims. 

1. A drum for a laundry washing machine comprising side walls defining a laundry receiving space, at least one of said side walls being circular and comprising a plurality of openings for the passage of a liquid therethrough, wherein said drain comprises at least a circular member circumferentially associated to an inner portion of said circular side wall, said circular member defining a chamber for receiving said liquid from at least one receiving opening of said openings and comprising at least one aperture facing said laundry receiving space suitable and serving to modify the flow of said liquid from the at least one receiving opening to said laundry receiving space.
 2. A drum according to claim 1, wherein said circular member is fixed to said inner portion of said circular side wall.
 3. A drum according to claim 1, wherein said circular member is associated to said inner portion of said circular side wall in a removable way.
 4. A drum according to claim 1, wherein said circular member is a portion of a circumference.
 5. A drum according to claim 1, wherein said circular member has a substantially U-shaped section.
 6. A drum according to claim 1, wherein the size of said at least one aperture is less than the size of said at least one receiving opening.
 7. A drum according to claim 1, wherein said plurality of openings of said circular side wall comprises a first plurality of openings and a second plurality of openings, wherein the size of said first plurality of openings is less than the size of said second plurality of openings.
 8. A drum according to claim 7, wherein said circular member is associated to said inner portion of said circular side wall in correspondence with said second plurality of openings.
 9. A drum according to claim 1, wherein at least one of said side walls is a rear side wall and said circular member is associated to said inner portion of said circular side wall in a position close to said rear side wall.
 10. A drum according to claim 1, wherein the drum further comprises at least one lifter associated to said inner portion of said circular side wall.
 11. A drum according to claim 10, wherein said at least one lifter defines a chamber for receiving said liquid from said at least one receiving opening and comprises at least one aperture facing said laundry receiving space and serving to modify the flow of said liquid from the at least one receiving opening to said laundry receiving space.
 12. A drum according to claim 11, wherein said chamber of said at least one lifter communicates with said chamber of said circular member.
 13. A drum according to claim 10, wherein said at least one lifter is fixed to said inner portion of said circular side wall.
 14. A drum according to claim 10, wherein said at least one lifter is associated to said inner portion of said circular side wall in a removable way.
 15. A drum according to claim 10, wherein said at least one lifter is fixed to said circular member.
 16. A drum according to claim 10, wherein said at least one lifter and said circular member are formed as a single piece construction.
 17. A laundry washing machine comprising a casing supporting a washing tub external to a washing drum suitable to receive the laundry to be washed, wherein said washing drum is a drum according to claim
 1. 18. A laundry washing machine comprising a casing supporting a washing tub external to a washing drum suitable to receive the laundry to be washed, wherein said washing drum is a drum according to claim
 7. 19. A laundry washing machine comprising a casing supporting a washing tub external to a washing drum suitable to receive the laundry to be washed, wherein said washing drum is a drum according to claim
 8. 20. A laundry washing machine comprising a casing supporting a washing tub external to a washing drum suitable to receive the laundry to be washed, wherein said washing drum is a drum according to claim
 11. 